I was travelling with the UN refugee agency UNHCR to observe the refugee crisis in the north of the country. There are more than 180,000 refugees in camps on the border and, because of the rainy season and extreme flooding, conditions are really difficult. Help from the international community is badly needed right now. I also wanted to visit because I hadn't been to South Sudan since it became independent a year ago. I was born and raised in Wau [the third-biggest city] until the age of eight or nine. Then, due to the civil war, my family became refugees and eventually we had to flee the country. I never believed that independence would actually happen, so to go back and experience the sense of unity that had been lost in the civil war – it was just overwhelming.

Has the country changed a great deal since you left?

The capital Juba is growing so rapidly it's unbelievable. There's so much potential, but it takes time for a country to find its feet after independence, especially when people have been fighting a war. We need better healthcare and education – and not just education for boys. Girls are dying in childbirth before eighth grade – that's like 14 years old. That's how old I was when I went to England. I was lucky because my father worked on the board of education and I was educated from the age of six. If I hadn't had that, I don't know if I would have made the same decisions in my life.

Having lived in London and New York for 21 years, do you feel any less Sudanese?

I was born and raised there and my mother is still very strongly connected to the Dinka culture. If it was up to her we would be back living at home, marrying Dinka men, having Dinka kids. Do I feel like an outsider when I go back? No, not really. I love it there and I'm trying to help with the rebuilding process; I don't want people to go through all that bloodshed ever again. I know what it feels like not knowing if you'll have food on your table the next day or walking miles and miles through the bush where all you can eat is grass.

Do you still speak Dinka?

Yes, but when people talk to me they laugh, because I've got quite a funky accent. I still speak Arabic too, because that's what I was writing in school.

You were approached by a modelling scout in London when you were 18. Did that come as a surprise?

Of course! At the time, I'd been in the country for five years. I'd had to adjust to a new culture, learn how to speak a new language. I was working part-time as a cleaner while I was going to college and then babysitting after school. I had a lot on my plate. The scout had to assure me that it wasn't dodgy. Then I had to go home and deal with Mother. She said absolutely not – "go to school, get your degree … "

But you did it anyway.

The agency advised me to go to New York in the summer holidays; I could always go back to school if it didn't work out. I'm the kind of person who doesn't like to regret things so I went to New York and I went around all the ad agencies, photographers, stylists. Steven Meisel [the fashion photographer] gave me a second call and booked me for Italian Vogue. They tried to put me in this wig for the photo-shoot, and he was like: "No, just put on this dress and go for it." When I realised I could just be myself, that was it.

As a model, do you feel the pressure of getting older?

I'm glad I still look 10 years old! OK, maybe I'm pushing it. The fashion business is actually more relaxed than it was 10 or 20 years ago – you can get married and have kids, for instance, and still have a good career. The lifestyle is demanding though – most of your time is spent in planes and hotel rooms. I feel really bad for my ex-boyfriend. It was like: "Hi, good to see you, gotta go." So now I'm taking much more time out. I model in moderation so I can also do other things…

Such as?

Being involved with UNHCR is the most important thing. I've always loved to paint – I was studying to do an art degree when I was approached to become a model – and I've being doing some design work as well. I also love just having a quiet time, sitting in my little library at home in Brooklyn and reading or watching documentaries or listening to music.

Coming from a family of nine children, do you think about having children of your own?

Oh yeah. That's part of the reason why I'm modelling in moderation. I feel like a 16-year-old now with the dates. Also, I'm getting pressure from my mother. Every time I go home, we all know what question is going to come up at the dinner table…

Any answers yet to that question?

I don't want to jinx it but I've met some lovely fellas. One of them is English. I'm going to leave it at that.

Do you still feel a connection with London?

London is like my second home. I've still got friends there from school and from when I first started in the modelling business – people such as Karen Elson, Jasmine Guinness, Jade Parfitt. But I also like just kicking back at my mum's and eating okra stew and njera and catching up with my family.

What music are you listening to at the moment?

People such as Norah Jones, Sade, Alicia Keys, and also some African music. Recently, I've been listening to a girl called Ayak – she has a really good voice.

I really wanted to come back to London for them. I'll be watching a young man called Guor Marial who is running the marathon. South Sudan doesn't have an Olympic body yet, so he's running as an independent. And I'll be watching Luol Deng playing for the British basketball team. His family lived four doors down from us in London and my older sisters knew his older sisters. It's a small world when you're from South Sudan.